You can compile the Linux client without the GUI component by using
Once installed and running you can configure the Linux client from the server web interface (use the default directories to debug to configure the backup paths).
If you want to configure the client as internet client, you need to supply the server name, port and the authkey (assuming there already is an internet client with the name `hostname`. See http://www.urbackup.org/Administration_Manual.php#x1-200006.2) via:
internet_mode_enabled=true" > /usr/local/var/urbackup/data/settings.cfg
You can start the client via
urbackupclientbackend -i -v debug
to see if it can establish the connection sucessfully.